UHPLC-MS/MS同时测定牛奶中5种头孢类药物残留

Simultaneous Determination of Five Cephalosporins Residues in Milk by UHPLC-MS/MS

关键词:  超高效液相色谱-串联质谱法  固相萃取  牛奶  头孢菌素类药物残留

Key words:  UHPLC-MS/MS  solid phase extraction  milk  cephalosporins residues

摘要:

目的 建立采用UHPLC-MS/MS同时测定牛奶中5种头孢菌素类药物残留的方法。方法 牛奶样品（约5 g）加10 mL Na₂EDTA-McIlvaine提取液提取后，涡旋离心，取中层清液，加入0.1 mol·L^-1 NaOH溶液调节pH至8.5，取上清液过HLB固相萃取柱富集并净化。富集浓缩后以Waters ACQUITY UPLC BEH（2.1 mm×50 mm，1.7 μm）色谱柱为分离柱，以0.1%甲酸溶液和乙腈为流动相进行梯度洗脱。采用电喷雾正离子源，以多反应监测模式进行质谱检测。结果 牛奶中5种头孢菌素类药物在1~20倍定量限浓度范围内有良好的线性关系，所得回收率为88.1%~114%，重复性试验RSD（n=6）均<6.55%，检出限为0.7~1.6 μg·kg^-1。结论 本方法专属性好、灵敏度高、准确性好，可多组分同时测定牛奶中的头孢类药物残留。

Abstract:

OBJECTIVE To establish a method for simultaneous determination of 5 cephalosporins residues in milk by UHPLC-MS/MS. METHODS Milk samples(about 5 g) were extracted by 10 mL Na₂EDTA-McIlvaine, centrifuged by a vortex, then get the middle-level clear liquid, the pH was adjusted to 8.5 by adding 0.1 mol·L^-1 NaOH solution, the supernatant were enriched and purified by HLB solid phase extraction column. The separation and analysis was performed on a Waters ACQUITY UPLC BEH(2.1 mm×50 mm, 1.7 μm) after enrichment and concentration. The mobile phase consisted of 0.1% formic acid and acetonitrile(gradient elution). Electrospray positive ion source was used for mass spectrometry detection by multiple reaction monitoring mode. RESULTS The five cephalosporins residues in milk had a good linear relationship within the quantitative limit of 20 times. The recoveries were 88.1%-114%, the RSD of repeatability test(n=6) was <6.55%, and the detection limit was 0.7-1.6 μg·kg^-1. CONCLUSION The method has good specificity, sensitivity and accuracy, and can be used for the simultaneous determination of cephalosporins residues in milk.